The answer is c, relying on renewable energy sources
Answer: 
Explanation:
Electron gain enthalpy is defined as energy released on addition of electron to an isolated gaseous atom.
The amount of energy released will be maximum when the tendency to attract electrons is maximum. As flourine has atomic number of 9 and has electronic configuration of 2,7. It can readily gain 1 electron to attain stable noble gas configuration and hence liberates maximum energy.
4 total bonds if u have double,or triple then subtract from 4
Polar covalent, it is what happens when there is unequal bond between two atoms, where one has a slightly negative charge and one has a slightly positive charge.
zero because its not going anywhere its stationary
hope this helped ^_^